Constraining Antarctic Ice Sheet Properties using Distributed Acoustic Sensing Data from the South Pole
Description:
Well-constrained properties of the South Pole subsurface are vital for understanding Antarctic ice sheet dynamics. Estimates of firn, ice, and sediment layer properties in the Antarctic ice sheet exist from traditional active source experiments using geophones, but their spatial resolution and extent are quite limited due to deployment challenges. Distributed acoustic sensing (DAS), a new tool in seismology that transforms fiber optic cables into dense arrays of strainmeters, has high spatial resolution, large spatial coverage, and relatively low-effort deployment, making it a promising tool for glacier seismology. In January 2023, we deployed a DAS unit on a long-range telecommunication cable from the QSPA South Pole station. This experiment allows for the accurate estimation of the ice sheet and bedrock properties from active and passive strain-rate recordings.
To calibrate the expected data recordings, we generate a set of synthetic experiments based on three geologic scenarios: 1) ice to bedrock, 2) ice to lithified sediment to bedrock, and 3) ice to dilatant sediment to bedrock. We apply a single-force source estimated from a previous active source experiment in Ridgecrest CA for accurate amplitude and frequency content, and convert the output synthetic displacements to strain-rate for comparability with the DAS data. Our synthetic data suggests the 8 kilometer cable records the triplicated P and S phase, allowing constraint of layer depths and wave speeds. Variations between the three models give insight into which end member case the acquired data likely represents. On the acquired data, we apply a surface-wave inversion strategy to estimate the seismic velocity and attenuation of the subsurface structure . These material properties can be used as a proxy for englacial temperature, which in turn provides insights on ice-sheet dynamics and better constraints for climate modeling.
Session: Understanding Earth Systems with Fiber-optic Cables [Poster]
Type: Poster
Date: 4/19/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Auden M. Reid-McLaughlin
Student Presenter: Yes
Invited Presentation:
Authors
Auden Reid-McLaughlin Presenting Author Corresponding Author areidmcl@caltech.edu California Institute of Technology |
Martin Karrenbach martin.karrenbach@seismicsunusual.com Seismics Unusual |
Zhongwen Zhan zwzhan@caltech.edu California Institute of Technology |
James Atterholt atterholt@caltech.edu California Institute of Technology |
Qiushi Zhai qzhai@caltech.edu California Institute of Technology |
Ettore Biondi ebiondi@caltech.edu California Institute of Technology |
Yan Yang yanyang@caltech.edu California Institute of Technology |
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Constraining Antarctic Ice Sheet Properties using Distributed Acoustic Sensing Data from the South Pole
Category
Understanding Earth Systems with Fiber-optic Cables